Plot series with strips in the background

Hi I want plot a time series (see below) with shade strips in the background. For example, if the data belongs to 1998, add a light grey strip behind the line. If it belongs to 1999, add a darker grey stripe behind the line and so on. I would also like to have a text box on each strip indicating the period of time. It seems to be a very challenging task for me. can someone help me?

thanks very much.

    '6/01/1998'     [  5.41]
    '9/01/1998'     [5.0933]
    '12/01/1998'    [  4.39]
    '3/01/1999'     [4.6633]
    '6/01/1999'     [  4.88]
    '9/01/1999'     [  5.16]
    '12/01/1999'    [5.6067]
    '3/01/2000'     [6.1867]
    '6/01/2000'     [6.2167]
    '9/01/2000'     [  6.13]
    '12/01/2000'    [   5.9]
    '3/01/2001'     [4.5967]
    '6/01/2001'     [  3.78]

Answer 1

[dpb]

OK, I did take a few minutes -- I'm certainly not adroit w/ patches so this is crude at best--but it gets the ideas across for starters, I think.

dn=datenum(dat(:,1),'m/dd/yyyy');   % create datenums for your time vector
plot(dn,[dat{:,2}].')               % and plot the data
xtk=datenum(1998,[1:6:13*4-1].',1); % tickmarks for quarters for yeears
xlim([xtk(1) xtk(end)])             % set limits to match
set(gca,'xtick',xtk)                % and the ticks
datetick('x',17,'keeplimits','keepticks')  % date format axis
xdata=[[xtk(1);xtk(3);xtk(3);xtk(1)] [xtk(3);xtk(5);xtk(5);xtk(3)]];
ydata=repmat([4.5 4.5 5.5 5.5].',1,2);  
cdata=[0.8 0.8 0.8];                    % a gray color, fairly dark
for i=1:size(xdata,2)                   % each year group defined
  p(i)=patch(xdata(:,i),ydata(:,i),cdata);  % draw each year patch
  set(p,'facealpha',0.3+0.1*i);             % alpha variably lighter to darker
end

The loop is where undoubtedly a better implementation could be made--I wasn't expert-enough in a short time to be able to fixup the alpha globally so took the easy way out of making multiple objects. That surely isn't necessary w/ a little more finesse...

doc patches  % for all the skinny--happy reading!  :)

ADDENDUM:

Oops, forgot about the text labels for the years...

xyr=datenum([1998:1999]',6,1);  % get the 1/1 year locations
text(xyr,5.5,datestr(xyr,'yyyy'), ...
   'horizontalalign','center','verticalalign','bottom')

[Linden]

Thanks very much. It's very helpful.

Answer 2

[Star Strider]

It took a while to get the patch working correctly, thus the delay.

This code:

C = {'6/01/1998'     [  5.41]
    '9/01/1998'     [5.0933]
    '12/01/1998'    [  4.39]
    '3/01/1999'     [4.6633]
    '6/01/1999'     [  4.88]
    '9/01/1999'     [  5.16]
    '12/01/1999'    [5.6067]
    '3/01/2000'     [6.1867]
    '6/01/2000'     [6.2167]
    '9/01/2000'     [  6.13]
    '12/01/2000'    [   5.9]
    '3/01/2001'     [4.5967]
    '6/01/2001'     [  3.78]};

Cd = datenum(C(:,1), 'mm/dd/yyyy');
Cn = cell2mat(C(:,2));
Cv = datevec(Cd);
[Cyu, ia, ic] = unique(Cv(:,1));
ia = [ia; size(Cd,1)];

figure(1)
plot(Cd, Cn, '-g')
datetick('x', 'mm/dd/yyyy')
cm = colormap(gray(size(ia,1)+1))*0.20+0.40
ysv = ylim;
hold on
for k1 = 1:size(ia,1)-1
    X = [Cd(ia(k1)) Cd(ia(k1)) Cd(ia(k1+1)) Cd(ia(k1+1)) Cd(ia(k1))]'
    Y = [ysv fliplr(ysv) ysv(1)]'
    patch(X, Y, cm(k1,:))
end
plot(Cd, Cn, '-g', 'LineWidth',2)
hold off

produced this plot:

You may want to experiment with the colormap line to get the result you want. I plotted the line in green in order to make it easily visible against the background.

[Linden]

Thanks a lot. Really appreciated.